1. Field of the Invention
This invention relates to steel mill blast furnace casthouses which employ controls for the suppression of fume formation and more particularly to those systems which employ hoods which cover the blast furnace taphole during casting.
When the taphole is covered by a hood it is not possible to directly sight the taphole to observe when the molten material ceases to flow as a stream from the furnace, which indicates the end of the cast. At the end of the cast it is necessary to remove the hood in order to make room for the mudgun to be swung into position for plugging the taphole. It is important to be able to sense, or anticipate, when the cast is completed in order to deter checking of the furnace and to minimize any deterioration of the hood which might occur.
2. Description of Prior Art
The present invention is ancillary to the invention disclosed and claimed in pending U.S. patent application Ser. No. 190,130 (filed Sept. 24, 1980), which is owned by the assignee of the invention described in this application and is incorporated by reference herein.
U.S. patent application Ser. No. 190,130 describes method and apparatus for the suppression and mitigation of fumes from iron troughs and iron and slag runners of blast furnace casting systems. There it is disclosed that the known prior art fume pollution control systems are addressed to the ventilation or exhausting of fumes after they are formed, primarily by circulating air to function as a carrier and coolant of the fumes before collection in a baghouse, or the like. In contrast, application Ser. No. 190,130 is addressed to minimizing the causal effects, i.e., the formation of fumes due to oxidization of the iron, slag, and sulfur, by occluding oxidizing gases, primarily through the use of hoods or covers on the iron trough and the iron and slag runners.
It is believed there are no other presently known blast furnace casthouse pollutant control systems which cover the taphole with hoods without drafting air.